I think when you compared Butterfly Tenergy/Dignics and ESN tensor with Mark V or Sriver, you can easily see that there is tension built into Tenergy/Dignics/ESN tensors.
Now does the effect dissipate? I don't know because I am pretty sure an one-year old Tenergy sitting there, out of the package, is still a lot more catapulty than Mark V or Sriver.
Do I think they pre-tuned the rubber at the factory to make the catapult effects even more pronounced? Yes.
So what do I do? If I have an old sheet of Butterfly and/or ESN tensor rubber, I just give it one layer of booster before putting it on my blade.
That's it. I don't even thinking about it that much.
And old rubber that's never been used will still have catapult but will have lost a lot of feeling.
I avoid using boosted on euro rubbers because it's very easy to overboost them.
At this point I've boosted some 10 of my old rubber, and I've found that baby oil works perfectly with tensors. It doesn't add almost any speed, but gives life to the rubber, not like new, but a million times better than what it would be. And of course for old played rubbers, it works too.
It keeps the feeling for months as well, just doesn't ads any speed.